Few give Chisora, 28, much of a chance, but Klitschko has been quick to talk up his challenger's credentials and backed the Zimbabwe-born Briton to at least put up a decent fight.

Ran away

"David Haye didn't want to fight," said the veteran. "He just kept running away from my brother. He didn't come in to fight.

"I expect a better fight from Dereck Chisora. He's actually fighter. He wants to go in and fight and to go the distance. He tries to challenge his opponent and I didn't see that in the last fight between David Haye and Wladimir Klitschko.

"Dereck Chisora is more aggressive than David Haye."

Despite officially retiring in October, Haye is ready to fight again if a deal can be done to face Vitali, 40, or secure a rematch with his 35-year-old brother.

On-off talks have been going on for months but there is no light at the end of the tunnel.

"David Haye is so unpredictable and we tried to make a deal and I hope the fight comes through, but right now we are miles apart from agreeing the contract," Klitschko admitted.

"Right now I don't want to talk about it. I am focused totally on the Chisora fight and I hope that after Dereck Chisora, David Haye changes his mind and I can give a chance to David Haye to fight for a world title."

Klitschko has made no secret of his desire to go one better than his brother by knocking Haye out, such is the dislike they hold for the Englishman, and hopes that ambition can still be realised.

"I keep saying to David Haye, 'please fight me'," he said. "I say 'please fight for the world title; it's the most prestigious title in the world'.

"If he doesn't want to do that, it's okay. David Haye always tries to find excuses why fights do not happen. I hope David Haye one day makes a decision to fight me.